Asymmetric polymethine dyestuffs



Patented Sept. 20, 1932 UNITED STATES? PATENT oer-Ice OT'IMAR WAHL, OF LEVERKUsEN-ON-THE-R INE, ennivmngnssienon'ro ANIZLINE WORKS 1nd, on NEW YO'RI AT. 2., A GORPOBAIION OF DELAWARE ASYMMETRIC roLYMnrnINn DYE-STUFFS No Drawing. Application filed June 24,1929, Serial No. 373,474, and in Germany June :28, 1828.

The present invention relates to a process of preparing polymethine dyestufis and to the new products obtainable thereby, more particularly it relates to dyestuffs of the probable general formula: 1 Y

wherein the Rs represent alkyl groups, R for hydrogen or alkyl,: a: stands fora monovalent radical of a strong inorganic 7 acid and 3 stands for a radical of the benzene at about O'to about 40 C. and keeping the reaction mixture at this temperature, stirring being continued. In this manner the above identified dyestufl, in which y represents the cyano group or a dinitrobenzene nucleus are obtainable. The reaction mixture is poured into water and filtered while hot from a resinous residue eventually present. On

cooling the dyestuif crystallizes; if desiredv the separation of the dyestufl' can be favored by the addition of common salt. The process proceeds according to the following scheme:

benzene nucleus are obtainable by. first causng a primaryor secondary'amine to' react with a pyridinium cyano halogeniide or a dinitrophenyl pyridinium chloride (compare W. Konig, Journal fiir praktische Chemie,

R l R O R VO R subst. +011, g gs? substdT--oHa N IL .1 R

the- Rs meaning allzyl groups, 00 a monovalent acid radical and subst. any substituents, advantageously while gently heating the reaction mixture, say between aboutQO and about C. A goodmethod of carrying out my process consists in dissolving the pyridinium salt in acetic acid anhydride, and slowly introducing while stirring the 1.3.3- trialkyI-Q-methylene-indoline while heating vol. 69, page 105, and Zinclre, Annalen de-r Chemie,vol. 33() page 3 61). and then reaota ing upon the compound formed with an aboutequimolecular quantity of av1.3.3 -trialkyl-Z-rnethylene indoline in acetic acid anhydride, favorably while gently heating, say between about 20 andabout 70 C; generally'Iheat the mixture aboutBO toc about 40 C. 1 o

The whole process may be represented by the following scheme:

greenish crystalline powder, it dyes tanned R" meaning alkyl, R the dinitrophenyl residue or the cyano group, R; an aromatic nucleus, R hydrogen or alkyl and m a monovalent acid radical of a strong inorganic acid. My new dyestuffs are generally dark metallic lustrous powders, difiicultl'y soluble in cold water, dyeing blue to green shades.

The invention is illustrated by the following examples, without being limited thereto:

Emample 1.1 mol of dinitrophenyl pyridinium chloride-and 1 mol of 1.3.3-trimethyl- 2-methylene indoline are introduced into acetic acid anhydride. The mixture is heated to about 35 C. and kept at this temperature while stirring; then it is poured into hot water and filtered, On cooling the dyestuif crystallizes; it has the following formula:

and dyes tanned cotton bluish-green shades.

The corresponding dyestuflt' from 5-amido-r 1.3.3-trimethyl-2-methylene indoline dyes somewhat greener shades.

Example 2.1 mol of the yellow dyestuflI' of the formula:

H: bl Ha ture is stirred for several hours. The melt The corresponding dyestuff from 5'-amino"- 1.3.3-trimethyl-2-methylene bluish green shades.

Iclaim; 1. The process which comprises heating in acetic acid anhydride solution about aquimolecular quantities of a compound of the general formula: I

indoline dyes 2. The process which comprises'h-eating in acetic acid anhydride solution about equi- "-molecular'quantities of a'compound" of the generalformula I 3. The process which comprises heating acetic acid anhydride solution about equimoene indoline between aboutQO and 'about lecular quantities of a compound of the formula:

and 1.3.3-trimethyl-2-m'ethylene indoline at about 30 to about 40 C.

4. As new products the dyestuffs of the probable general formula:

wherein R stands for hydrogen or an alkyl group, a: stands for a monovalent radical of a strong inorganic acid, y stands for a substituent of the group consisting of the cyano group and a radical of the benzene series, and

the Rs stand for alkyl groups, said dyestuffs being generally dark metallic lustrous powders, diflicultly soluble in cold water, dyeing blue to green shades.

5. As new products the dyestuffs of the probable general formula:

wherein R and R stand for alkyl groups, and w stands for a monovalent radical of a strong inorganic acid, said dyestufis being generally dark metallic lustrous powders, diflicultly soluble in cold water, dyeing blue to green shades.

6. As a new product the dyestufi of the following formula:

said dyestufl being a dark green metallic lustrous powder, dyeing tanned cotton greenish-blue shades.

In testimony whereof I have hereunto set my hand.

V OTTMAR WAHL. 

